The present invention relates to a device for instantaneously starting a fluorescent lamp with a starter composed of a nonlinear capacitor and a semiconductor device. More particularly, the invention relates to fluorescent lamp starting device which can instantaneously start a fluorescent lamp and for which no modification of a conventional fluorescent lamp fixture is required.
A variety of techniques for starting a fluorescent lamp employing a glow starting system in which an electronic starter is provided in the glow starter socket of a fluorescent lamp fixture have been proposed in the art. However, these techniques have found practical application only for small wattage fluorescent lamps of 10 W (FL 10) or smaller and not for fluorescent lamps of 15 W (FL 15) or higher because the former can be started merely by applying the standard AC supply voltage, 115 V for instance, while about 600 V is necessary to start the latter or larger types.
FIG. 1 is a circuit diagram of a known type of electronic starter for a FL 10 fluorescent lamp. In FIG. 1, reference numeral 1 designates a bi-directional thyristor, 2 a diode, 3 a capacitor, 4 a fluorescent lamp, 5 filaments, and 6 a stabilizer. This circuit functions only to preheat the lamp filaments 5 and generates no high voltage pulses. Since the circuit is made up of only three components, it is small enough to be mounted in a glow starter case such as specified by JIS C 7603 (relating to fluorescent lamp glow starters).
As stated above, it is necessary to provide a pulse voltage of 600 V or higher to start a fluorescent lamp of 15 W or higher. Accordingly, an electronic starter should perform both a filament preheating function and a pulse generating function.
A variety of circuits have been employed for such an electronic starter. One known type of circuit is shown in FIG. 2 in which reference numeral 6 designates a stabilizer, 5 filaments, 2 a diode, 7 a choke coil with a ferrite core, 1 a bi-directional thyristor, 3a and 3b capacitors, and 8 a resistor. Typical ratings and sizes of these components are as indicated in Table 1 below:
TABLE 1 ______________________________________ Component Rating Size (mm) ______________________________________ Choke coil (7) 200 mH 19 .times. 17 .times. 17 Capacitor (3a) 0.68 .mu.F 200VDC 18 .times. 17 .times. 9 Capacitor (3b) 0.002 .mu.F 1000VDC 26 .times. 11 .0. ______________________________________
The diode 2 and the bi-directional thyristor 1 can be miniaturized by providing them in the form of a semiconductor chip and the resistor 8 also can be miniaturized by employing a thick film resistor. However, it is difficult using presently avilable techniques to miniaturize the choke coil 7 and the capacitors 3a and 3b listed in Table 1, and therefore, it is impossible to assemble the above-described components within the volume allowed for a glow starter. That is, the external size of an electronic starter for a fluorescent lamp of 15 W (FL 15) or higher is several times as larger as that of a glow starter which prevents the miniaturization and standardization of electronic starters.